Membrane enzyme reactor with simultaneous separation using electrophoresis

A membrane enzyme reactor with simultaneous separation was investigated. Enzymes, urease and aspartase, were immobilized by a porous polytetrafluoroethylene membrane. Electrical field was applied in the medium while the reaction was carried out. Products with electrical charge could be separated through the membrane from the reaction medium as they were formed. Reaction behavior was analyzed by a simple model considering both pore-migration and reaction in the skelton of the membrane. According to the analysis the inherent reaction rate of the immobilized enzymes decreases significantly. This is probably caused by the structural variation of enzymes. For the case of urease, the change of pH inside the membrane may also cause the decrease of the reaction rate. The model analysis showed that the enzyme content in the membrane and the residence time of the substrate in the membrane governed overall extent of reaction.List of Symbols e g (dm³)^–1 enzyme concentration in the membrane - L cm membrane thickness - K _m mM Michaelis constant - Rate mmol · min^–1 · g^–1 rate of product formation per unit weight of enzyme - S mM substrate concentration - S _in mM inlet substrate concentration - S _out mM outlet substrate concentration - u cm · min^–1 migration rate - V V voltage between the electrodes - V _m mmol · min^–1 · g^–1 maximum reaction rate - X conversion - z cm distance from the surface inside the membrane - void fraction of the porous membrane - tortuosity of the membrane - min space time     

A kinetic analysis of enzyme systems involving four substrates

A treatment of kinetic data for enzyme mechanisms involving four substrates is described. The initial-rate equations and product-inhibition patterns for such mechanisms are presented. The treatment is extended to include analysis of enzyme mechanisms involving three substrates in which two molecules of one substrate are used.     

The Northern and Southeastern Ojibwa: serum proteins and red cell enzyme systems

Two Ojibwa Indian populations in Ontario, selected to represent the Northern (Pikangikum Band) and Southeastern (Wikwemikong Band) branches of this “tribe” are compared for their serum protein and red cell enzyme systems. Albumin, haptoglobin, immunoglobins Gm and Inv, serum α-globulin and transferrin polymorphisms are reported. The genetic markers Al^Naskapi and Gc^Chippewa are found in both groups, Tf^{D Chi} in Pikangikum only. Contrary to expectations, the Mongoloid marker Gm^1,3,5,11 was found in neither population. Ceruloplasmin is invariant in both, all individuals being B homozygotes. For the red cell enzymes, only the common phenotypes of glucose 6-phosphate dehydrogenase and peptidases A and B are present in the Northern and Southeastern Ojibwa. Isocitrate dehydrogenase, lactate dehydrogenase, nucleoside phosphorylase, phosphofructokinase, phosphoglucomutase II, phosphoglyeerate kinase and peptidase C were typed in Pikangikum only: no variants were found. Methemoglobin reductase, tested in Wikwemikong alone, is invariant. Loci polymorphic in at least one Ojibwa group include acid phosphatase, adenosine deaminase, adenylate kinase, glutathione reductase, phosphogluconate dehydrogenase, phosphoglucomutase I, and soluble glutamic oxalocetic transaminase. Comparisons are made with other Algonkian-speakers when possible, with other North American, South American and Asiatic Mongoloid populations when sufficient Algonkian data do not exist. The causes of genetic heterogeneity between the two Ojibwa groups are discussed.     

Expansion of the D system of horse red cell alloantigens

Two additional specificities (Dq and Dr) were assigned to the D system of horse red cell alloantigens following discussion of the 1989 ISAG Horse Comparison Test (HCT) results. Family and population data support 25 phenogroups defined by the enhanced battery of 17 D system factors.     

Advances in hereditary red cell enzyme anomalies

Conclusions From the above report we can observe that recent advances in hereditary disorders of red cell enzymes concern molecular mechanisms of the defect and relationship between molecular anomalies and pathologic consequences. Moreover, congenital nonspherocytic hemolytic anemias of undertermined cause are becoming fewer.It seems to us that the perspectives opened in this field could develop in two ways. Firstly, the current possibility of obtaining homogeneous mutant enzymes (for pyruvate kinase, glucose phosphate isomerase, glucose-6-phosphate dehydrogenase, phosphoglycerate kinase) should enable the study of the structure-function relationship, as was done for hemoglobin. Secondly, the recent progress in genetic analysis and genetic engineering could provide a direct approach of the nature of the genetic defect at the DNA level. This should be fundamental to understand the nature of some enzyme deficiencies without any detectable abnormal product of a mutant gene (e.g., glucose phosphate isomerase deficiencies with silent gene and M-type phosphofructokinase deficiency).     

A rapid method for differentiation of dairy lactic acid bacteria by enzyme systems

Summary A rapid and simple technique utilizing the APIZYM enzymatic patterns complemented with arginine dihydrolase and citratase was developed for species differentiation of 40 lactic acid bacteria relevant to the dairy industry.Streptococcus species in general produced no -galactosidase, except forStreptococcus thermophilus. Lactobacillus species showed strong aminopeptidases and galactosidases but contained no arginine dihydrolase and citratase. Among the group N-streptococci,Streptococcus diacetylactis produced citratase, whereasStreptococcus cremoris differed by the production of butyrate esterase.Streptococcus faecalis was readily distinguishable fromStreptococcus lactis by butyrate esterase activity that was the basis of the differential agar developed. Heterofermentative lactobacilli differed from homofermentative lactobacilli in possessing arginine dihydrolase and citratase but by not producing leucine-aminopeptidase.